- Production of enantiopure chiral epoxides with e. Coli expressing styrene monooxygenase
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Styrene monooxygenases are a group of highly selective enzymes able to catalyse the epoxidation of alkenes to corresponding chiral epoxides in excellent enantiopurity. Chiral compounds containing oxirane ring or products of their hydrolysis represent key building blocks and precursors in organic synthesis in the pharmaceutical industry, and many of them are produced on an industrial scale. Two-component recombinant styrene monooxygenase (SMO) from Marinobacterium litorale was expressed as a fused protein (StyAL2StyB) in Escherichia coli BL21(DE3). By high cell density fermentation, 35 gDCW/L of biomass with overexpressed SMO was produced. SMO exhibited excellent stability, broad substrate specificity, and enantioselectivity, as it remained active for months and converted a group of alkenes to corresponding chiral epoxides in high enantiomeric excess (>95–99% ee). Optically pure (S)-4-chlorostyrene oxide, (S)-allylbenzene oxide, (2R,5R)-1,2:5,6-diepoxyhexane, 2-(3-bromopropyl)oxirane, and (S)-4-(oxiran-2-yl)butan-1-ol were prepared by whole-cell SMO.
- ?tadániová, Radka,Fischer, Róbert,Gyuranová, Dominika,Hegyi, Zuzana,Rebro?, Martin
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- One-pot method for preparing diepoxide (by machine translation)
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The method comprises the following steps, adding a reducing agent water solution :S1. to a reactor: slowly dropwise adding a reducing agent aqueous solution to obtain the diepoxide, adding a reducing agent aqueous solution to the reactor, to obtain the diepoxy, and separating and purifying ;S2. from the organic phase: by one-pot reaction, and adding a reducing agent water, through a pot method to obtain the diepoxide crude solution, to obtain the diepoxide compound. The invention discloses a method for separating and purifying a diepoxide crude product through a high vacuum, distillation . The method comprises the following steps of: adding a reducing agent aqueous solution to the, reactor at a low temperature, to obtain a diepoxide 91% crude, product through 95% a, one-pot reaction, of the diolefin and the m-chloroperoxybenzoic acid solution to obtain a diepoxide crude product solution. (by machine translation)
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Paragraph 0085-0092
(2020/05/01)
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- NOVEL BETA-HYDROXYLATED TERTIARY DIAMINES, A PROCESS FOR THEIR SYNTHESIS AND THEIR USE FOR ELIMINATING ACID COMPOUNDS A GASEOUS EFFLUENT
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The invention relates to novel nitrogen compounds belonging to the family of tertiary diamines of general formula (I) below, wherein R is an alkanediyl radical —(CH2)n- with n=2, 3, 4, 5 or 6. The compound according to the invention is for example N,N,N′,N′-(tetramethyl)-1,6-diamino-2,5-hexanediol or N,N,N′,N′-(tetramethyl)-1,8-diamino-2,7-octanediol. The invention also relates to the method for preparing them and to their use for removing acid compounds contained in a gaseous effluent.
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Paragraph 0159; 0160; 0161; 0162; 0163; 0164; 0165-0167
(2017/04/11)
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- METHOD FOR PRODUCING EPOXY COMPOUND BY OXIDATION
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The present invention provides a method for producing an epoxy compound by oxidation using hydrogen peroxide, in which the generation of oxygen due to the decomposition of hydrogen peroxide can be suppressed in the system, and which does not require complicated post-treatment, is excellent in reactivity, and allows the reaction to be performed in a SUS vessel. The present invention relates to a method for producing an epoxy compound, the method comprising reacting an olefin compound with hydrogen peroxide in the presence of a nitrile compound and a silicate. The silicate is preferably at least one selected from sodium silicate and potassium silicate.
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Paragraph 0040
(2013/06/27)
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- Absolute configuration for 1, n-glycols: A nonempirical approach to long-range stereochemical determination
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The absolute configurations of 1,n-glycols (n = 2-12, 16) bearing two chiral centers were rapidly determined via exciton-coupled circular dichroism (ECCD) using a tris(pentafluorophenyl)porphyrin (TPFP porphyrin) tweezer system in a nonempirical fashion devoid of chemical derivatization. A unique "side-on" approach of the porphyrin tweezer relative to the diol guest molecule is suggested as the mode of complexation.
- Li, Xiaoyong,Burrell, Carmin E.,Staples, Richard J.,Borhan, Babak
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supporting information; experimental part
p. 9026 - 9029
(2012/07/13)
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- Synthesis of water-soluble multidentate aminoalcohol β-cyclodextrin derivatives via epoxide opening
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New highly soluble β-aminoalcohol β-cyclodextrin (β-CD) derivatives have been synthesized via nucleophilic epoxide opening reactions with mono-6-amino mono-6-deoxy-permethyl-β-CD and mono-6-amino mono-6-deoxy-β-CD. The binding properties of the β-CD were enhanced by linking aminoalcohol subunits which caused its solubility to improve markedly. The reaction conditions were optimised using microwave irradiation giving moderate-to-good yields with a series of epoxides. A regioselective epoxide opening reaction was observed in the reaction with styrene oxide while the stereoselectivity was strictly dependent on substrate structure.
- Martina,Caporaso,Tagliapietra,Heropoulos,Rosati,Cravotto
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experimental part
p. 2677 - 2682
(2012/01/03)
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- Synthesis and mechanistic studies of a mitomycin dimer containing an eight-membered cyclic disulfide
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Dimeric DNA alkylating agents have drawn significant interest because these compounds are expected to provide at least two reactive sites and as a result, generate enhanced levels of DNA interstrand cross-link (DNA ISC) adducts compared to their monomeric agents. We report the synthesis and mechanistic studies of a novel mitomycin dimer, 7-N,7′-N′-(1″,2″- dithiocanyl-3″,8″-dimethylenyl)bismitomycin C (8) connected by an eight-membered cyclic disulfide. Mitomycins require prior activation (i.e., transformation to a good electrophile) for DNA adduction and therefore, 8 was aimed to undergo facile nucleophilic activation and produce enhanced levels of DNA ISC. At the core of this function lies a cyclic disulfide in 8. It was expected that disulfide cleavage by an appropriate nucleophile would successively produce two thiols that may trigger activation of two mitomycin rings in a dimer through intramolecular cyclization to quinine rings. Compound 8 was synthesized from mitomycin A (1) and the key intermediate, cyclic disulfide (11), along with the reference diol mitomycin 7-N,7′-N′-(2″, 7″-dihydroxy-1″,8″-octanediyl)bismitomycin C (23) which does not contain the disulfide unit. We found that 8 underwent significantly enhanced nucleophilic activation in the presence of Et3P compared with 23, and that the disulfide unit in 8 played a key role for the nucleophilic activation. Based on these findings, we proposed a mechanism for nucleophilic activation of 8. We further demonstrated that 8 generated much higher levels of DNA ISC (94%) compared with 23 (4%) and 2 (3%) in the presence of Et 3P (and l-DTT) leading to the conclusion that 8 is more efficient for DNA ISC processes than 23 and 2 due to the role of disulfide unit.
- Park, Hyun Jung,Kim, Jae Jin,Kim, Hyoung Rae,Lee, Eun Kyung,Kim, Eun Sook,Jeong, Choon Sik,Moon, Aree,Lee, Sang Hyup
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scheme or table
p. 4004 - 4013
(2011/08/06)
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- A simple and effective catalytic system for epoxidation of aliphatic terminal alkenes with manganese(II) as the catalyst
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A simple catalytic system that uses commercially available manganese(II) Perchlorate as the catalyst and peracetic acid as the oxidant is found to be very effective in the epoxidation of aliphatic terminal alkenes with high product selectivity at ambient temperature. Many terminal alkenes are epoxidised efficiently on a gram scale in less than an hour to give excellent yields of isolated product (>90%) of epoxides in high purity. Kinetic studies with some C9-alkenes show that the catalytic system is more efficient in epoxidising terminal alkenes than internal alkenes, which is contrary to most commonly known epoxidation systems. The reaction rate for epoxidation decreases in the order: 1-nonene>cis-3-nonene> trans-3-nonene. ESI-MS and EPR spectroscopic studies suggest that the active form of the catalyst is a high-valent oligonuclear manganese species, which probably functions as the oxygen atomtransfer agent in the epoxidation reaction.
- Ho, Kam-Piu,Wong, Wing-Leung,Lam, Kin-Ming,Lai, Cheuk-Piu,Chan, Tak Hang,Wong, Kwok-Yin
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experimental part
p. 7988 - 7996
(2009/11/30)
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- Iterative tandem catalysis of secondary diols and diesters to chiral polyesters
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The well-known dynamic kinetic resolution of secondary alcohols and esters was extended to secondary diols and diesters to afford chiral polyesters. This process is an example of iterative tandem catalysis (ITC), a polymerization method where the concurrent action of two fundamentally different catalysts is required to achieve chain growth. In order to procure chiral polyesters of high enantiomeric excess value (ee) and good molecular weight, the catalysts employed need to be complementary and compatible during the polymerization reaction. We here show that Shvo's catalyst and Novozym 435 fulfil these requirements. The optimal polymerization conditions of 1,1′-(1,3-phenylene) diethanol (1,3-diol) and diisopropyl adipate required 2mol% Shvo's catalyst and 12 mg Novozym 435 per mmol alcohol group in the presence of 0.5 M 2,4-dimethyl-3- pentanol as the hydrogen donor. With these conditions, chiral polyesters were obtained with peak molecular weights up to 15kDa, an ee value up to 99% and with 1-3% ketone end groups. Also with the structural isomer, 1,4-diol, a chiral polyester was obtained, albeit with lower molecular weight (8.3 kDa) and slightly lower ee (94%). Aliphatic secondary diols also resulted in enantio-enriched polymers but at most an ee of 46% was obtained with molecular weights in the range of 3.33.7 kDa. This low ee originates from the intrinsic low enantioselectivity of Novozym 435 for this type of secondary aliphatic diols. The results presented here show that ITC can be applied to procure chiral polyesters with good molecular weight and high ee from optically inactive AA-BB type monomers.
- Van As, Bart A.C.,Van Buijtenen, Jeroen,Mes, Tristan,Palmans, Anja R.A.,Meijer
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p. 8325 - 8332
(2008/09/16)
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- Design of a highly efficient catalyst for the oxaziridinium-mediated epoxidation of olefins by Oxone
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2,3,3-Trimethyl-7-nitro-3,4-dihydroisoquinolinium tetrafluoroborate is a highly efficient catalyst for the oxaziridinium-mediated epoxidation of a variety of olefins, including monosubstituted ones.
- Bohé, Luis,Kammoun, Majed
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p. 747 - 751
(2007/10/03)
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- Synthesis of Cyclic Organic Carbonates from C3-C16 Epoxides
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Cyclic organic carbonates were prepared from epoxides (derivatives of C3-C16 olefins, C4 and C8 dienes, styrene; epichlorohydrin) in the presence of a catalytic system consisting of CoCl2 · 6H2O and dimethylformamide.
- Rybina,Srednev,Bobyleva
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p. 842 - 843
(2007/10/03)
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- Environmentally friendly catalysis using supported reagents: Catalytic epoxidation using a chemically modified silica gel1
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A new heterogeneous catalyst based on a chemically modified mesoporous silica gel possessing immobilised cobalt ions is developed and successfully applied to the epoxidation of alkenes.
- Butterworth, Andrew J.,Clark, James H.,Walton, Paul H.,Barlow, Simon J.
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p. 1859 - 1860
(2007/10/03)
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- Preparation of Di- and polynitrates by ring-opening nitration of epoxides by dinitrogen pentoxide (N2O5)
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Eighteen epoxides of various kinds were reacted with N2O5 in chlorinated hydrocarbon solvents (principally CH2Cl2) to give vicinal nitrate ester products by a novel ring-opening nitration reaction. The procedure offers easier temperature control and simpler isolation procedures compared with conventional mixed acid nitrations; it also enables selective nitration reactions to be carried out on polyfunctional substrates. The scope and limitations of the reaction, as well as those of an alternative route utilising N2O4 with in situ oxidation of an intermediate nitrite-nitrate, are discussed.
- Golding, Peter,Millar, Ross W.,Paul, Norman C.,Richards, David H.
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p. 7037 - 7050
(2007/10/02)
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